Protective role of Puralpha to cisplatin.
BACKGROUND
The nucleic acid-binding protein Puralpha is involved at stalled DNA replication forks, in double-strand break (DSB) DNA repair and the cellular response to DNA replication stress. Puralpha also regulates homologous recombination-directed DNA repair (HRR).


RESULTS
Cells lacking Puralpha showed enhanced sensitivity to cisplatin as evaluated by assays for cell viability and cell clonogenicity. This was seen both in Puralpha-negative MEFs and in human glioblastoma cells treated with siRNA directed against Puralpha. MEFs lacking Puralpha also showed enhanced H2AX phosphorylation in response to cisplatin. Repair of a reporter plasmid that had been treated with cisplatin was decreased in a reactivation assay using Puralpha-negative MEFs and the capacity of nuclear extracts from Puralpha-negative MEFs to perform non-homologous end-joining in vitro was also impaired.


METHODS
We investigated the effects of the DNA damage-inducing cancer chemotherapeutic agent cisplatin on mouse embryo fibroblasts (MEFs) from PURA(-/-) knockout mice that lack Puralpha.


CONCLUSIONS
Puralpha has a role in the cellular response to cisplatin-induced DNA damage and may provide new therapeutic modalities for cisplatin-resistant tumors.
Kaminski
Rafal
R
Department of Neuroscience, Center for Neurovirology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Darbinyan
Armine
A
Merabova
Nana
N
Deshmane
Satish L
SL
White
Martyn K
MK
Khalili
Kamel
K
D000818:Animals; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D003114:Colony-Forming Units Assay; D004249:DNA Damage; D004260:DNA Repair / Q000502:physiology*; D004261:DNA Replication / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000502:physiology* / Q000627:therapeutic use; D005347:Fibroblasts / Q000187:drug effects / Q000502:physiology; D005909:Glioblastoma / Q000188:drug therapy / Q000235:genetics; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D051379:Mice; D009369:Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D014157:Transcription Factors / Q000172:deficiency / Q000502:physiology* / Q000627:therapeutic use
D004268:DNA-Binding Proteins; C501130:PURA protein, human; D014157:Transcription Factors; D006861:Hydrogen Peroxide; D002945:Cisplatin